Comparison of simultaneous esophageal pH monitoring and scintigraphy in infants with gastroesophageal reflux.

Twenty-nine infants under 1 yr of age were studied by simultaneous esophageal pH monitoring and scintigraphy for evaluation of gastroesophageal reflux (GER). Scintigraphy and pH monitoring were performed for 120 min after infants ingested their usual volume of formula. The number of reflux episodes during six 20-min intervals, as determined by both tests, were recorded. Esophageal pH monitoring was continued for 18-24 h. Sixteen of 29 patients exhibited GER by pH monitoring during the 2-h study. Gastroesophageal reflux occurred in seven of 29 during the first hour and 13 of 29 during the second hour. The mean time of first reflux episode detected by pH monitoring following the feeding was 82.4 +/- 49.3 min. In comparison, 28 of 29 patients had GER by scintigraphy during the 2 h. All 28 exhibited GER during the first hour, whereas only 22 of 29 patients exhibited GER during the second hour. The mean time of first episode of reflux by scintigraphy was 3.1 +/- 2.7 min. Forty-five percent of all reflux episodes detected by scintigraphy occurred during the first 20 min and 80% were detected during the first hour. In contrast, only 17% of reflux episodes were seen by pH monitoring during the first 20 min and 35% during the first hour; 65% of reflux episodes detected by pH monitoring were during the second hour. There was no correlation between the total number of reflux episodes detected by scintigraphy and 2-h esophageal pH monitoring during the 2-h study period (r = 0.326; p > 0.1). Overall, to detect reflux, scintigraphy was a more sensitive method than esophageal pH monitoring under the conditions of this study. Scintigraphy selectively detected reflux during the first 60 min post-prandially whereas pH monitoring was more likely to detect reflux beyond the first postprandial hour. These observations help to explain the lack of correlation between the two tests.